JPWO2002099154A1 - Fuel tank or fuel pipe excellent in corrosion resistance and method of manufacturing the same - Google Patents
Fuel tank or fuel pipe excellent in corrosion resistance and method of manufacturing the same Download PDFInfo
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- JPWO2002099154A1 JPWO2002099154A1 JP2003502261A JP2003502261A JPWO2002099154A1 JP WO2002099154 A1 JPWO2002099154 A1 JP WO2002099154A1 JP 2003502261 A JP2003502261 A JP 2003502261A JP 2003502261 A JP2003502261 A JP 2003502261A JP WO2002099154 A1 JPWO2002099154 A1 JP WO2002099154A1
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F13/00—Inhibiting corrosion of metals by anodic or cathodic protection
- C23F13/02—Inhibiting corrosion of metals by anodic or cathodic protection cathodic; Selection of conditions, parameters or procedures for cathodic protection, e.g. of electrical conditions
- C23F13/06—Constructional parts, or assemblies of cathodic-protection apparatus
- C23F13/08—Electrodes specially adapted for inhibiting corrosion by cathodic protection; Manufacture thereof; Conducting electric current thereto
- C23F13/12—Electrodes characterised by the material
- C23F13/14—Material for sacrificial anodes
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
- B60K15/03—Fuel tanks
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
- B60K15/03—Fuel tanks
- B60K15/04—Tank inlets
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C30/00—Coating with metallic material characterised only by the composition of the metallic material, i.e. not characterised by the coating process
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
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- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C4/00—Coating by spraying the coating material in the molten state, e.g. by flame, plasma or electric discharge
- C23C4/01—Selective coating, e.g. pattern coating, without pre-treatment of the material to be coated
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K15/00—Arrangement in connection with fuel supply of combustion engines or other fuel consuming energy converters, e.g. fuel cells; Mounting or construction of fuel tanks
- B60K15/03—Fuel tanks
- B60K2015/03328—Arrangements or special measures related to fuel tanks or fuel handling
- B60K2015/03453—Arrangements or special measures related to fuel tanks or fuel handling for fixing or mounting parts of the fuel tank together
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S428/00—Stock material or miscellaneous articles
- Y10S428/922—Static electricity metal bleed-off metallic stock
- Y10S428/9335—Product by special process
- Y10S428/937—Sprayed metal
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12014—All metal or with adjacent metals having metal particles
- Y10T428/12028—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
- Y10T428/12063—Nonparticulate metal component
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
- Y10T428/12556—Organic component
- Y10T428/12569—Synthetic resin
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
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- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12736—Al-base component
- Y10T428/1275—Next to Group VIII or IB metal-base component
- Y10T428/12757—Fe
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
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- Y10T428/12—All metal or with adjacent metals
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- Y10T428/12771—Transition metal-base component
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- Y10T428/12792—Zn-base component
- Y10T428/12799—Next to Fe-base component [e.g., galvanized]
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/12—All metal or with adjacent metals
- Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
- Y10T428/12771—Transition metal-base component
- Y10T428/12861—Group VIII or IB metal-base component
- Y10T428/12951—Fe-base component
- Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]
- Y10T428/12979—Containing more than 10% nonferrous elements [e.g., high alloy, stainless]
Abstract
特に外面の塩害環境下耐食性に優れた燃料タンクもしくは燃料パイプを提供するもので、質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として成型し、外面に溶接部やろう付け部および構成部品との接触隙間構造部を有し、これら外面部位の少なくとも一部に対して、３０℃の５％ＮａＣｌ水溶液中での電極電位が飽和カロメル電極基準で−０．４Ｖ以下となる金属を電気的に導通させて接配したことを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプ。In particular, to provide a fuel tank or a fuel pipe excellent in corrosion resistance under the salt damage environment on the outer surface. A steel plate or a steel pipe containing, by mass%, Cr: 9.0 to 25.0% is molded as a material and welded to the outer surface. Part, a brazing part, and a contact gap structure part with a component part. The electrode potential in a 5% NaCl aqueous solution at 30 ° C. with respect to at least a part of these outer surface parts is −0.05% based on a saturated calomel electrode. A fuel tank or a fuel pipe excellent in corrosion resistance, characterized in that a metal having a voltage of 4 V or less is electrically connected and connected.
Description
技術分野
本発明は、自動車用の燃料タンクおよび燃料パイプを始めとした燃料系部材に関し、特に外面の塩害環境下耐食性に優れた燃料タンクおよび燃料パイプに関する。
背景技術
昨今の環境保護ニーズやライフサイクルコスト低減のニーズは、自動車の構成部材である燃料タンクや燃料パイプなどの燃料系部材にまで波及している。
自動車用燃料タンクとして、永く鉛めっき鋼板を素材とし塗装を施したものが実用に供されてきたが、昨今の環境保護のニーズから脱鉛化の素材開発がなされてきている。また、塗装自体の環境負荷を重視し、従来のめっき鋼板において必要不可欠とされてきた塗装を省略しようとするニーズが生じてきている。
このような背景には、２００２年に米国カリフォルニア州で規定される予定のＬＥＶ−ＩＩ規制があり、燃料タンクとして１５年間もしくは１５万マイル走行の間のタンク寿命の保証が義務付けられることにある。
これを満たすためのタンク開発は、前記の塗装前提のめっき鋼材、樹脂、無塗装前提のステンレス鋼の３素材を中心として現在研究開発途上にある。これら３素材のうち、樹脂についてはリサイクル性が問題であり、めっき鋼材については重塗装が必要でコスト高と環境問題に逆行の嫌いがある。
現在注目されているのは、内面耐食性に何らの問題もないステンレス系素材を使ったタンクである。鉄系素材としてのリサイクル容易性を活かしつつ、従来のめっき鋼材で外面耐食性確保に必須とされた塗装を省略して、コスト／パフォーマンスを最大化しようと試みられている。
融雪塩環境下での外面耐食性で問題となる部位は、タンク成型に必須となる溶接部であり、溶接によるステンレス鋼素材表面の不働態皮膜破壊や隙間構造形成によって、素材の耐食機能が大きく損なわれるために、非溶接部は耐食的であっても溶接部では孔食、隙間腐食、応力腐食割れ（ＳＣＣ）といった局部腐食を引き起こす危険性がある。
これらの問題の解決策として汎用オーステナイト系鋼のＳＵＳ３０４Ｌなどが候補材とされているが、塩害条件ではＳＣＣを生じるという問題がある。このため、ＳＣＣ問題回避の素材としてフェライト系ステンレス鋼が有用となるが、Ｃｒ，Ｍｏといった合金元素の含有量が少ない素材では十分な塩害環境耐食性が得られない場合がある。
また、前記と同様の寿命向上は燃料タンクのみならず燃料パイプに対しても要求されており、曲げや拡管加工を受けた後、さらにろう付けや溶接施工されたり、金具との組立によって接触隙間が生じるなど、タンクの場合と同様に外面における局部腐食問題を抱えている。
このように、自動車用の燃料系部材にステンレス鋼を適用する場合は、内面の燃料環境における腐食問題は回避できるが、融雪塩に曝される外面において、孔食、隙間腐食、ＳＣＣといった局部腐食に対する抵抗性が課題となる。
発明の開示
本発明は、上述の問題を克服する技術を提供することを目的とするものであり、ステンレス鋼製燃料タンクや燃料パイプの溶接部、ろう付け部、隙間部等における局部腐食問題を解消するための手段を提供することを目的とする。
本発明者らは、種々のステンレス鋼板を素材として、燃料タンクの成型を模擬した溶接試験片を作製し、溶接部あるいは隙間部の腐食特性を評価してきた。
その結果、試験環境が苛酷な場合には、溶接ままの状態では、ＳＵＳ４３０鋼やＳＵＳ３０４鋼といった市販の汎用ステンレス鋼は、短期間で孔食や隙間腐食あるいはＳＣＣといった局部腐食が生じ、さらに、素材の合金元素含有量を高めたＳＵＳ４４４鋼やＳＵＳ３１６鋼でも、局部腐食の程度は軽減されるものの、局部腐食を完全に防止できないことを知見した。
したがって、ステンレス鋼製燃料タンクで長期間にわたって腐食問題を回避するには、何らかの防食方法を組み合わせる必要がある。またこのことは、燃料タンクのみならず、タンクと同様の環境に曝される燃料パイプについても当てはまる。
本発明者らが防食方法について種々検討した結果、燃料タンクや燃料パイプとして成型してしまった後に防食施工する以外に信頼性を確保できる方法がなく、溶接部や隙間部といった腐食発生部位に電気化学的に卑な金属を電気的導通を確保した状態で接配するのが最も有効かつ実用的であるとの結論を得た。
また、接配する金属としては、Ｚｎ，Ａｌ，Ｍｇ、あるいはこれらの合金が有効であるとの知見を得た。
Ｚｎ，Ａｌ，Ｍｇは鋼素材に対して卑な元素で、自らが腐食されることより鋼素材を防食するカソード防食作用をもつ元素であり、また、これらの合金も同様のカソード防食効果を奏することが知られており、このカソード防食作用は古くから船舶や海洋鋼構造物などに適用されてきている。
しかしながら、カソード防食は適正な防食電流が確保されて始めて成り立つものであり、塩害環境において燃料タンクや燃料パイプ表面に形成される極めて薄い液膜の条件では、電気抵抗が大きいため十分な防食電流を確保できない場合がある。このため単なるカソード防食作用では局部腐食を完全に防止するには不十分との見通しを得た。
このことは、普通鋼にＺｎ，Ａｌ，Ｍｇを接配して乾燥−湿潤を繰り返す複合サイクル試験と塩水浸漬試験を行って両結果を比較したところ、塩水浸漬では十分に防食されたが、液膜が薄いために十分な防食電流を確保できない複合サイクル試験では殆ど防食効果が発現されなかったことで確認された。
しかしながら、素材をステンレス鋼に変えて同様の比較を行ったところ、塩水浸漬と複合サイクル試験の防食効果がほぼ同等の結果を得た。すなわち、素材がステンレス鋼の場合は、カソード防食用金属は防食電流による単なるカソード防食効果に加えて、別の防食作用があることになる。この原因を調査解析した結果、接配した金属は自己腐食して生じる腐食生成物にｐＨを上昇させる作用があり、これによって鋼素材表面が弱アルカリ性に維持されるが、素材が普通鋼であれば弱アルカリ性環境でも腐食は軽減されないのに対し、素材がステンレス鋼の場合は、僅かなｐＨ上昇によって不働態皮膜の局部破壊が大幅に抑制され、腐食が軽減されることを知見した。
すなわち、ステンレス鋼にカソード防食用の金属を接配すると、防食電流とｐＨ上昇の２つの防食効果が得られ、液膜が薄くて防食電流が小さい複合サイクル試験の場合でもｐＨ上昇効果によって防食が達成されるのである。さらに、このｐＨ上昇効果を享受するためのステンレス鋼素材としての必要条件として、最も重要な要素はＣｒ含有量であることを知見した。
以上のように、自動車の塩害環境という特殊な環境条件において、Ｃｒが適正量のステンレス鋼に対してのみ、Ｚｎ，Ａｌ，Ｍｇやこれらの合金の接配が有効に作用することを解明した。また、前記の２つの防食効果をより安定的に発現させ得るための接配金属の組成や接配のあり方についても解明した。
本発明は上記知見に基づいて構成したものであり、その要旨は以下の通りである。
（１）質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として成型し、外面に溶接部やろう付け部および構成部品との接触隙間構造部を有し、これら外面部位の少なくとも一部に対して、３０℃の５％ＮａＣｌ水溶液中での電極電位が飽和カロメル電極基準で−０．４Ｖ以下となる金属を電気的に導通させて接配したことを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプ。
（２）燃料タンクまたは燃料パイプの外面に接配される金属の組成が、不可避的不純物を除く実質的成分がＺｎ，Ａｌ，Ｍｇの１種または２種以上から成ることを特徴とする前記（１）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（３）燃料タンクまたは燃料パイプの外面に接配される金属の組成が、質量％で、Ｚｎ：１０％以上を含有し、残部が実質的にＡｌからなることを特徴とする前記（１）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（４）燃料タンクもしくは燃料パイプの外面に接配される金属の組成が、質量％で、Ｚｎ：１０％以上を含有し、さらにＳｉ：１〜１０％、Ｓｎ：１〜１０％、Ｍｇ：１〜１０％の１種または２種以上を含有し、残部が実質的にＡｌからなることを特徴とする前記（１）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（５）燃料タンクもしくは燃料パイプの外面に接配される物質に含まれる金属において、ＭｇとＳｉあるいはＭｇとＳｎから成る金属間化合物の１種以上をさらに含有することを特徴とする前記（４）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（６）接配される金属が厚さ１０μｍ以上の箔であることを特徴とする前記（１）〜（５）のいずれか１項に記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（７）金属箔表面に該金属の溶出を抑制する有機物層または無機物層を設けたことを特徴とする前記（６）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（８）燃料タンクもしくは燃料パイプの外面に接配される金属が溶射粒体であり、厚さ１０μｍ以上の積層構造を有する膜として接配されたことを特徴とする前記（１）〜（５）のいずれか１項に記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（９）金属粉体または粒体の積層構造膜の膜表面あるいは膜内空隙に有機物または無機物層を形成したことを特徴とする前記（８）に記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（１０）平均粒径１〜１００μｍの粉体または粒体の金属と樹脂から成り、質量％で金属含有量が７５％以上となる膜を１０μｍ以上の厚さで燃料タンクもしくは燃料パイプの外面に形成したことを特徴とする前記（１）〜（５）のいずれか１項に記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（１１）ウレタン結合が含まれる樹脂であることを特徴とする前記（１０）記載の耐食性に優れた燃料タンクもしくは燃料パイプ。
（１２）質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として冷間で塑性加工を施し、構成部品を接合、締結した後、外面の溶接部やろう付け部および構成部品との接触隙間構造部の一部に対して、前記（１）〜（５）のいずれか１項に記載の組成から成る厚さ１０μｍ以上の金属箔を貼付することを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
（１３）金属箔を貼付した後に、金属箔表面に該金属の溶出を抑制する有機物層または無機物層を設けることを特徴とする前記（１２）記載の耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
（１４）質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として冷間で塑性加工を施し、構成部品を接合、締結した後、外面の溶接部やろう付け部および構成部品との接触隙間構造部の一部に対して、前記（１）〜（５）のいずれか１項に記載の組成から成る厚さ１０μｍ以上の金属層を溶射することを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
（１５）金属層を溶射した後に、溶射金属層表面あるいは溶射金属層内部の該金属の溶出を抑制する有機物層または無機物層を設けることを特徴とする前記（１２）記載の耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
（１６）質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として冷間で塑性加工を施し、構成部品を接合、締結した後、外面の溶接部やろう付け部および構成部品との接触隙間構造部の一部に対して、前記（１）〜（５）のいずれか１項に記載の組成から成る平均粒径１〜１００μｍの粉体または粒体の金属と樹脂から成り、質量％で金属含有量が７５％以上となる膜を１０μｍ以上の厚さで外面に塗装することを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
（１７）質量％で、Ｃｒ：９．０〜２５．０％を含有する鋼板または鋼管を素材として冷間で塑性加工を施し、構成部品を接合、締結した後、外面の溶接部やろう付け部および構成部品との接触隙間構造部の一部に対して、前記（１）〜（５）のいずれか１項に記載の組成から成る平均粒径１〜１００μｍの粉体または粒体の金属とイソシアネート系樹脂から成る塗料を塗装することにより、厚さ１０μｍ以上かつ金属含有量が質量％で７５％以上となる塗膜を形成させることを特徴とする耐食性に優れた燃料タンクもしくは燃料パイプの製造方法。
発明を実施するための最良の形態
以下、本発明について詳細に説明する。
先ず、本発明における燃料タンクあるいは燃料パイプ用素材としては、Ｃｒ：９〜２５％を含有する鋼板あるいは鋼管とする。
Ｃｒは素材の耐食性を支配する主要元素であり、９％を下回ると接配金属のｐＨ上昇効果を十分に享受できず外面耐食性が不十分となる。一方、Ｃｒは固溶強化元素であり、２５％を超えて含有させると素材の延性が劣化して十分な冷間加工性が得られなくなる。このため、素材のＣｒ含有量は９〜２５％に限定する。
Ｃｒ以外の合金元素、例えばＮｉ，Ｍｏ，Ｃｕなどについては、公知の技術に従って適宜含有させて良い。ただし、これらの元素を含有させる場合でも、Ｃｒ量としては前記範囲を満たすことを必要条件とする。
前記のＣｒを含有する鋼板あるいは鋼管は、プレス加工、曲げ加工、拡管、絞り加工といった冷間での塑性加工やシーム溶接、スポット溶接、プロジェクション溶接といった溶接やろう付け、あるいは金具の取り付けなどの通常の成型、組立工程を経て燃料タンクや燃料パイプに成型されるが、この成型が完了した後の燃料タンクおよび燃料パイプにおいて、塩害環境に曝される外面に対して防食施工を加えるものとする。特に、溶接部やろう付け部、金具との接触隙間構造部において孔食、隙間腐食、ＳＣＣといった局部腐食感受性が高いため、少なくともこれらの部位の一部に施工することを必要条件とする。
隙間構造部においては、隙間開口部のサイズが十分に大きい場合には隙間外部に加えて隙間内部にも施工するのがより望ましい。この他に引張残留応力の高い非溶接部位などにも施工しておくのが望ましい。なお、ここで言う溶接部やろう付け部とは、溶接やろう付けの熱によって不働態皮膜が破壊され変色した部位、溶接やろう付けによって形成された隙間構造部位、ろう付けのろう材料部を総称する。
次に、接配する金属について述べる。
本発明における外面防食は、カソード防食効果と素材表面ｐＨ上昇効果の２つの効果を利用する。したがって接配される金属としては、少なくともステンレス素材に対して十分に卑でなければならない。本発明では、そのガイドラインとして、３０℃、５％ＮａＣｌ水溶液中で測定される電極電位が飽和カロメル電極基準で−０．４Ｖ以下となることを必要条件とした。
なお、電位の測定は、２４時間にわたって計測し、その間の最高値をもって代表値と定義する。この電位は、ステンレス鋼の腐食隙間再不働態化電位に相当するものであり、これ以下の電位を有する金属が接配されることにより、ステンレス鋼素材の電位が腐食隙間再不働態化電位以下に低下することによって、隙間腐食の成長を抑止できるためである。
この条件を満たす代表的金属元素としてＺｎ，Ａｌ，Ｍｇが挙げられる。中でもＺｎは、カソード防食効果に加えて、ステンレス鋼素材表面のｐＨ上昇効果に優れる。自己腐食によって生じる塩基性炭酸亜鉛がｐＨをアルカリ域まで上昇させるので、Ｚｎを接配すると防食電流の到達範囲を超える部位においてもＺｎの錆汁が展開されていれば、素材の腐食が抑制されるのである。このため、Ｚｎは本発明における目的達成手段として最も有効な金属である。
Ａｌは、外面塩害環境においてステンレス鋼に対して卑な金属であり、カソード防食効果は確保できる。Ａｌは自己腐食速度がＺｎより小さいため、長期にわたってカソード防食効果を確保するには有用な金属である。しかしながら、ｐＨ上昇効果はＺｎに比べて劣るため、防食電流到達可能範囲を超える部位を防食する場合には、ＺｎやＭｇなどとの合金として用いるのが望ましい。
Ｍｇは、Ｚｎより卑な金属であり、抵抗の大きい薄液膜条件でのカソード防食に適している。しかし、Ｍｇの自己腐食速度はＺｎより大きいため、防食電流を広範に到達させ得る反面、短期間に消耗する。またｐＨ上昇効果もＺｎに比べて劣る。このため、長期のカソード防食効果とｐＨ上昇効果を確保するには、ＭｇはＺｎやＡｌなどとの合金として用いるのが望ましい。
カソード防食効果とｐＨ上昇効果の２つを極大化させつつ自己腐食速度を低下させる金属系としては、Ｚｎを１０％以上含有し、残部がＡｌ、またはＡｌ，Ｍｇ，Ｓｉ、またはＡｌ，Ｍｇ，Ｓｎ、またはＡｌ，Ｍｇ，Ｓｉ，Ｓｎよりなる合金が有効である。これら合金におけるＺｎ含有量としては、カソード防食効果とＺｎの錆汁によるｐＨ上昇効果を十分に確保するとの観点から、Ｚｎ含有量として１０％を最小量とする必要がある。
Ｍｇは、Ａｌ−Ｍｇ−Ｓｉ−Ｚｎ系、またはＡｌ−Ｍｇ−Ｓｎ−Ｚｎ系、またはＡｌ−Ｍｇ−Ｓｉ−Ｓｎ−Ｚｎ系の合金において、ＳｉあるいはＳｎと水溶性金属間化合物を形成し、ｐＨ上昇効果を有すると共に素地に防食皮膜を形成して腐食を抑制する。このためＭｇを合金元素として利用する場合は、Ｓｉ，Ｓｎ，Ａｌ，Ｚｎと共に利用することとし、金属間化合物を形成するに十分な含有量に制限することとし、１〜１０％を適正範囲とする。
Ｓｉ，Ｓｎは、Ｍｇと共に水溶性金属間化合物Ｍｇ２Ｓｉ，Ｍｇ２Ｓｎを形成し防食に有効に作用する。このため、Ｍｇを利用する場合に共に含有させる。その含有量はＭｇとの金属間化合物の形成に必要となる範囲とし、１〜１０％が適正である。
以上の組成よりなる金属または合金の接配の形態としては、燃料タンクあるいは燃料パイプの本体外面と電気的導通が確保されていれば良く、特に規定するものではないが、導電性物質を含む有機物を介した接着もしくは粘着、溶射、金属粉末含有塗料としての塗装、溶接、ろう付け、あるいはクリップやボルトナットを使った機械的な固定などの方法が常套であり、望ましい形態としては、箔として腐食懸念部位に貼付する方法、粉体あるいは粒体として腐食懸念部位に積層成膜する方法、金属含有量の高い塗料として塗装成膜する方法が挙げられる。
溶接部や隙間部といった腐食懸念部位の防食に箔状金属を用いる場合、箔の厚みは、長期防食の観点から１０μｍ以上が必要であり、望ましくは５０μｍ以上が適当である。さらに、箔の腐食消耗を抑制するために、箔表面を環境から遮断する有機物層や無機物層を設けるのが望ましい。有機物層としては一般に用いられる樹脂系塗料で十分であり、無機物層としてはクロメート皮膜などが有効である。
粉体あるいは粒体を積層皮膜構造として成膜すると、箔の場合よりも素材に対する接配金属の比表面積が大きくなるので防食効果が増大する。紛体や粒体を簡便に成膜するには溶射法が適している。この場合、成膜厚みは少なくとも１０μｍ以上が必要であり、望ましくは５０μｍ以上が適当である。
一方、比表面積の大きい分だけ消耗が早いので、膜の腐食寿命を延長する観点から、膜表面および膜内粒子を環境から遮断する有機物層や無機物層を設けるのが望ましい。有機物層としては、一般に用いられる樹脂系塗料で十分であり、無機物層としてはクロメート皮膜などが有効である。なお、溶射手段としては、特に規定する必要はなく、通常のフレーム溶射法などで十分である。
金属粉末含有塗料として腐食懸念部位に塗装成膜する方法は、導電性を確保し、かつ接配金属の腐食損耗を抑制できる簡便方法として最も優れる形態である。この場合、導電性を確保するための金属粉末含有量は、塗膜に対し質量％で７５％以上である必要がある。含有される金属粉末のサイズは平均粒径として１〜１００μｍが適正であり、大き過ぎると塗装作業性が低下し、小さすぎると金属紛の消耗が早く防食効果が低下する。望ましい金属粉末サイズは２〜２０μｍである。また、塗膜厚みとしては少なくとも１０μｍ以上が必要であり、望ましくは５０μｍ以上が適当である。
塗料の樹脂成分は、塗膜密着性確保の観点から、エポキシ系あるいはウレタン系が望ましいが、特に耐水密着性に優れるウレタン系が最適である。
エポキシ系樹脂を用いる場合は、十分な密着性を確保するために、ブラスト処理やペーパー研磨などによって下地を目粗しする必要があるが、ウレタン樹脂系の場合は密着性に優れるため、下地の目粗しは不要であり、生産性の点からも燃料タンクや燃料パイプの製造に好適である。
また、ウレタン樹脂はイソシアネートとポリオールや水などの水酸基を有する化合物との重合によって生成されるが、塗装作業性の点から大気中の湿気と重合して硬化するイソシアネート系樹脂から成る１液型のものを用いるのが望ましい。この場合、硬化時間を短縮する目的で、必要に応じてアミンなどの硬化促進剤を適量添加しても良い。
なお、塗装手段としては特に規定する必要はなく、通常のスプレー塗装などが常套である。
実施例
以下、実施例に基づいて本発明をより詳細に説明する。
（実施例１）
表１に示す組成の板厚０．８ｍｍの鋼板から、燃料タンクのフランジ部を模擬して図１に示す寸法形状のシーム溶接試験片を作製した。図において、符号１は２枚の供試材、２は供試材１に接配する合金箔で、（ａ）図右側の斜線部分はその接着領域を示す。（ａ）図のＡ−Ａ′断面を（ｂ）図に示す。３は供試材１のシール、４は供試材１の溶接部、５は２枚の供試材の隙間部、６は供試材１と合金箔２とを接着する導電性接着剤層である。
この溶接部４に対して、種々の組成の合金箔２（厚み０．２ｍｍ）を導電接着剤６で接着させて、腐食試験に供した。また、一部の試験条件では合金箔２の表面にウレタン・エポキシ樹脂系塗膜を形成させたものを用いた。
腐食試験としては、タンク外面の塩害環境を想定し、ＪＡＳＯモードの複合サイクル試験（５％ＮａＣｌ溶液噴霧、３５℃、２時間→強制乾燥、６０℃、４時間→湿潤９０％ＲＨ，５０℃，２時間）を３００サイクルにわたって実施した。
試験終了後、溶接部および隙間内部の局部腐食の程度と合金薄板の腐食厚みを評価した。局部腐食深さおよび合金消耗厚みの元板厚に対する割合が２０％以下であれば、良好と評価し、６０％を超える場合には実用的でないと評価し、２０〜６０％の場合はリスク有りと評価した。
試験条件および結果を表２に示す。Ｎｏ．１〜１２の本発明では、溶接部および隙間部で満足すべき防食効果が得られている。Ｎｏ．８では合金消耗量が多いが、Ｎｏ．１のように表面塗装によってＺｎの消耗を抑制することで、防食効果を延長することができる。
一方、比較例Ｎｏ．１０１，１０２，１０３，１０４は、溶接ままで供試しており溶接部、隙間部の腐食が激しく、γ系ステンレス鋼を素材とした場合にはＳＣＣが発生する。
（実施例２）
実施例１と同様に、表１に示す組成の板厚０．８ｍｍの鋼板から、燃料タンクのフランジ部を模擬して図２に示す寸法形状のシーム溶接試験片を作製した。図２において、１は２枚の供試材、２ａは供試材１に接配する合金の溶射層もしくは合金粉末含有塗料の塗膜で、（ａ）図右側の斜線部分はその溶射もしくは塗装領域を示す。（ａ）図のＡ−Ａ′断面を（ｂ）図に示す。３は供試材１のシール、４は供試材１溶接部、５は２枚の供試材の隙間部である。
溶射は、大気中のフレーム溶射法で施し、溶射層の厚みは８〜２００μｍとした。一部の試験片について、溶射後にクロム酸−シリカ系のクロメート処理を施した。付着量はＣｒ換算で溶射層表面１ｍ２あたり２０ｍｇとした。
塗装は、種々の組成の合金粉末（平均粒径：３μｍ）とイソシアネートからなる塗料をスプレー塗装後、常温の室内にて硬化させ、塗膜厚み８〜１００μｍ、塗膜中合金含有量を質量％で６８〜８５％として成膜した。腐食試験方法および評価方法は、実施例１と同様とした。
表３に溶射材の試験条件と結果を示す。Ｎｏ．２１〜３２の本発明では、溶接部および隙間部で満足すべき防食効果が得られている。Ｎｏ．２８では溶射層の消耗量が多いが、Ｎｏ．２１のように溶射後のクロメート処理によってＺｎの消耗を抑制し、防食効果を延長することができる。
一方、比較例Ｎｏ．２０１は、溶射厚みが本発明の範囲を外れており、十分な防食効果が得られていない。また、比較例Ｎｏ．２０２は、素材が本発明の成分範囲を外れているため、隙間部の防食が不十分である。
表４に塗装材の試験条件と結果を示す。Ｎｏ．４１〜５２の本発明では、溶接部および隙間部で満足すべき防食効果が得られている。
一方、比較例Ｎｏ．３０１〜３０３は、塗膜中の金属含有量が、比較例Ｎｏ．３０４は塗膜厚みが、そして比較例Ｎｏ．３０５は素材の成分が本発明の範囲を外れているため、溶接部もしくは隙間部の防食が不十分である。
（実施例３）
表１の組成から成る鋼管を素材として、燃料パイプにおけるブリーザーチューブとの接合部を模擬した図３、図４の寸法形状の銀ろう付け試験片を作製した。
図３は、銀ろう付け部に合金箔を接配する場合の試験片形状を示す。図中、７は供試材の燃料パイプ本体、８はブリーザーチューブで７と同一材料、９は管端部のシール、１０は銀ろう付け部、１１は合金箔で、（ａ）図中央の斜線部分はその接着領域を示す。（ａ）図のＡ−Ａ′断面を（ｂ）図に示す。（ｂ）図において、１０は銀ろう、１１は合金箔、１２は銀ろう付け部と合金箔とを接着する導電性接着剤層である。
図４は、銀ろう付け部に溶射もしくは塗装によって合金を接配した場合の試験片形状を示す。図中、７は供試材の燃料パイプ本体、８はブリーザーチューブで７と同一材料、９は管端部のシール、１０は銀ろう付け部、１１ａは溶射もしくは塗装部位である。（ａ）図のＡ−Ａ′断面を（ｂ）図に示す。（ｂ）図において、１０は銀ろう、１１ａは溶射層もしくは塗膜である。
この銀ろう付け部に対して、種々の組成の合金箔（厚み、０．２ｍｍ）を導電接着剤で接着させたもの、種々の組成の合金を厚み０．１ｍｍで溶射したもの、種々の組成の合金粉末（平均粒径：３μｍ）とイソシアネートからなる塗料をスプレー塗装し、塗膜厚み８０μｍ、塗膜中合金含有量：８０％として成膜したものを準備し、腐食試験に供した。また、一部の試験条件では合金箔や合金溶射層の表面にウレタン・エポキシ樹脂系塗膜を形成させたものを用いた。腐食試験方法および評価方法は、実施例１と同様とした。
試験条件および結果を表５に示す。Ｎｏ．６１〜７２の本発明では、溶接部および隙間部で満足すべき防食効果が得られている。
一方、比較例Ｎｏ．４０１〜４０５は、銀ろう付けままで供試しており、ろう付け部の局部腐食やＳＣＣが発生する。比較例Ｎｏ．４０５は素材の成分が本発明の範囲を外れているため、防食施工を施しても十分な効果が得られない。
以上述べたように、本発明によって、溶接部や隙間部の局部腐食問題を回避でき、耐食性に優れた燃料タンクもしくは燃料パイプが得られる。本発明の思想は燃料タンクと燃料パイプの個別部品のみに限定されるものではなく、外面塩害環境に曝される自動車用部材において、規定の必要条件を満たすステンレス鋼が適用される全ての部材および部品に適用可能である。
【図面の簡単な説明】
図１（ａ）は燃料タンクのフランジ部分を模擬した腐食試験片で、導電性接着剤層を設けて金属箔を貼付した例を示す。
図１（ｂ）は図１（ａ）のＡ−Ａ′断面図である。
図２（ａ）は燃料タンクのフランジ部分を模擬した腐食試験片の形状寸法を示す。
図２（ｂ）は図１（ａ）のＡ−Ａ′断面図である。
図３（ａ）は燃料パイプにおけるブリーザーチューブとのろう付け部を模擬した腐食試験片の形状で、金属箔を貼付した例を示す。
図３（ｂ）は図３（ａ）のＡ−Ａ′断面図である。
図４（ａ）は燃料パイプにおけるブリーザーチューブとのろう付け部を模擬した腐食試験片の形状で、溶射層または塗膜を形成させた例を示す。
図４（ｂ）は図４（ａ）のＡ−Ａ′断面図である。TECHNICAL FIELD The present invention relates to a fuel system member such as a fuel tank and a fuel pipe for an automobile, and more particularly to a fuel tank and a fuel pipe which are excellent in corrosion resistance under a salt damage environment on an outer surface.
2. Description of the Related Art The needs for environmental protection and life cycle cost reduction in recent years have spread to fuel-related members such as fuel tanks and fuel pipes, which are components of automobiles.
As fuel tanks for automobiles, those coated with lead-plated steel sheets have been used for a long time, but the use of lead-free materials has been developed due to recent environmental protection needs. Further, there is a need to place importance on the environmental load of the coating itself and to omit the coating which has been indispensable for the conventional plated steel sheet.
Against this background, there is the LEV-II regulation stipulated in California, USA, in 2002, which requires the fuel tank to have a guaranteed tank life of 15 years or 150,000 miles.
The development of tanks to meet this is currently under research and development, centering on the three materials of plated steel, resin, and stainless steel, which is not coated, as described above. Among these three materials, resin is problematic in terms of recyclability, and plated steel is required to be heavily painted.
At present, attention is being paid to tanks made of stainless steel materials, which have no problem with internal corrosion resistance. Attempts have been made to maximize cost / performance by omitting the coating which is essential for ensuring the outer surface corrosion resistance of conventional plated steel while taking advantage of the ease of recycling as an iron-based material.
The part that poses a problem in the outer surface corrosion resistance in a snowmelt salt environment is the welded part that is indispensable for tank molding, and the corrosion resistance function of the material is greatly impaired by the destruction of the passive film on the surface of the stainless steel material and the formation of the gap structure by welding. Therefore, even if the non-welded portion is corrosion-resistant, there is a risk of causing local corrosion such as pitting, crevice corrosion, and stress corrosion cracking (SCC) in the welded portion.
As a solution to these problems, general-purpose austenitic steel such as SUS304L is a candidate material, but there is a problem that SCC is generated under salt damage conditions. For this reason, ferritic stainless steel is useful as a material for avoiding the SCC problem, but a material having a low content of alloying elements such as Cr and Mo may not be able to obtain sufficient salt damage environmental corrosion resistance.
In addition, the same service life improvement as above is required not only for fuel tanks but also for fuel pipes. After bending and pipe expansion, brazing and welding are performed, and contact gaps are assembled by fitting with metal fittings. As in the case of the tank, there is a problem of local corrosion on the outer surface, such as the occurrence of corrosion.
As described above, when stainless steel is applied to a fuel system member for automobiles, corrosion problems in the fuel environment on the inner surface can be avoided, but local corrosion such as pitting, crevice corrosion, and SCC on the outer surface exposed to snow melting salt. Is a problem.
DISCLOSURE OF THE INVENTION An object of the present invention is to provide a technique for overcoming the above-mentioned problems, and to solve a local corrosion problem in a welded portion of a stainless steel fuel tank or a fuel pipe, a brazed portion, a gap portion, or the like. It is intended to provide a means for solving the problem.
The present inventors have prepared welding test pieces simulating the molding of a fuel tank using various stainless steel sheets as materials, and have evaluated the corrosion characteristics of welded portions or gaps.
As a result, when the test environment is severe, a commercially available general-purpose stainless steel such as SUS430 steel or SUS304 steel in the as-welded state causes local corrosion such as pitting, crevice corrosion or SCC in a short period of time, It has been found that even with SUS444 steel or SUS316 steel with an increased content of alloying elements, the degree of local corrosion is reduced but local corrosion cannot be completely prevented.
Therefore, in order to avoid the corrosion problem for a long time in a stainless steel fuel tank, it is necessary to combine some anticorrosion methods. This applies not only to the fuel tank but also to the fuel pipe exposed to the same environment as the tank.
The present inventors have conducted various studies on anticorrosion methods. As a result, there is no method that can ensure reliability other than performing anticorrosion work after molding as a fuel tank or fuel pipe, and electric power is applied to corrosion occurrence sites such as welds and gaps. It has been concluded that it is most effective and practical to connect chemically base metals while ensuring electrical continuity.
In addition, it has been found that Zn, Al, Mg, or an alloy thereof is effective as a metal to be in contact.
Zn, Al, and Mg are elements that are base with respect to the steel material and are elements that have a cathodic protection effect of preventing corrosion of the steel material by being corroded by itself, and their alloys also exhibit the same cathodic protection effect. It is known that this cathodic protection action has been applied to ships, marine steel structures and the like since ancient times.
However, cathodic protection is only feasible when an appropriate anticorrosion current is secured.Under conditions of extremely thin liquid film formed on the surface of fuel tanks and fuel pipes in a salt damage environment, a sufficient anticorrosion current cannot be obtained due to high electrical resistance. In some cases, it cannot be secured. For this reason, it has been predicted that simple cathodic protection is not sufficient to completely prevent local corrosion.
This was confirmed by comparing the results of a combined cycle test in which Zn, Al, and Mg were placed in contact with ordinary steel to repeat drying and wetting, and a salt water immersion test. The results were sufficiently protected by salt water immersion. It was confirmed that in the combined cycle test in which a sufficient anticorrosion current could not be secured because the film was thin, almost no anticorrosion effect was exhibited.
However, when the same comparison was performed with the material changed to stainless steel, the results obtained were substantially the same as those of the salt water immersion and the combined cycle test. That is, when the material is stainless steel, the cathodic protection metal has another anticorrosion action in addition to the mere cathodic protection effect by the anticorrosion current. As a result of investigating and analyzing the cause, the metals in contact with each other have the effect of raising the pH of the corrosion products generated by self-corrosion, which maintains the surface of the steel material slightly alkaline. It has been found that corrosion is not reduced even in a weakly alkaline environment, whereas when the material is stainless steel, a slight increase in pH significantly suppresses local destruction of the passive film and reduces corrosion.
In other words, when a metal for cathodic protection is placed in contact with stainless steel, two corrosion protection effects of a corrosion protection current and a pH rise are obtained, and even in the case of a combined cycle test in which the liquid film is thin and the corrosion protection current is small, the corrosion protection is achieved by the pH rise effect. It is achieved. Furthermore, it has been found that the most important factor as a necessary condition for a stainless steel material to enjoy this pH increasing effect is the Cr content.
As described above, it has been clarified that, under special environmental conditions such as a salt damage environment of an automobile, Zn, Al, Mg and alloys of these alloys effectively act only on stainless steel containing an appropriate amount of Cr. In addition, the composition of the metal in contact with the metal and the method of the metal connection for more stably exhibiting the above two anticorrosive effects were clarified.
The present invention has been made based on the above findings, and the gist is as follows.
(1) A steel sheet or a steel pipe containing, by mass%, Cr: 9.0 to 25.0%, is molded as a material, and has a weld gap, a braze, and a contact gap structure with component parts on an outer surface, A metal whose electrode potential in a 5% NaCl aqueous solution at 30 ° C. is −0.4 V or less based on a saturated calomel electrode is electrically connected to at least a part of these outer surface portions. Fuel tank or fuel pipe with excellent corrosion resistance.
(2) The composition of the metal disposed on the outer surface of the fuel tank or the fuel pipe, wherein a substantial component excluding unavoidable impurities is composed of one or more of Zn, Al, and Mg. 1) A fuel tank or a fuel pipe having excellent corrosion resistance as described above.
(3) The composition according to (1), wherein the composition of the metal disposed on the outer surface of the fuel tank or the fuel pipe contains 10% or more by mass of Zn in mass%, and the balance substantially consists of Al. A fuel tank or fuel pipe with excellent corrosion resistance as described.
(4) The composition of the metal disposed on the outer surface of the fuel tank or fuel pipe is, by mass%, containing Zn: 10% or more, and further, Si: 1 to 10%, Sn: 1 to 10%, and Mg: The fuel tank or fuel pipe having excellent corrosion resistance according to the above (1), wherein 1 to 10% of one or more kinds are contained, and the balance is substantially made of Al.
(5) The metal contained in the substance disposed in contact with the outer surface of the fuel tank or the fuel pipe, further comprising at least one intermetallic compound of Mg and Si or Mg and Sn. 2.) A fuel tank or fuel pipe having excellent corrosion resistance as described above.
(6) The fuel tank or fuel pipe excellent in corrosion resistance according to any one of (1) to (5), wherein the metal to be disposed is a foil having a thickness of 10 μm or more.
(7) The fuel tank or fuel pipe excellent in corrosion resistance according to (6), wherein an organic layer or an inorganic layer for suppressing elution of the metal is provided on the surface of the metal foil.
(8) The metal according to (1) to (5), wherein the metal disposed on the outer surface of the fuel tank or the fuel pipe is a sprayed particle and is disposed as a film having a laminated structure with a thickness of 10 μm or more. The fuel tank or the fuel pipe having excellent corrosion resistance according to any one of the above items.
(9) The fuel tank or fuel pipe excellent in corrosion resistance according to (8), wherein an organic or inorganic layer is formed on the surface of the film or the voids in the film of the laminated structure film of metal powder or granules.
(10) A film made of metal or resin of powder or granules having an average particle size of 1 to 100 μm and having a metal content of 75% or more by mass% on the outer surface of a fuel tank or a fuel pipe with a thickness of 10 μm or more. The fuel tank or fuel pipe according to any one of the above (1) to (5), wherein the fuel tank or the fuel pipe has excellent corrosion resistance.
(11) The fuel tank or fuel pipe excellent in corrosion resistance according to (10), which is a resin containing a urethane bond.
(12) A steel plate or a steel pipe containing 9.0 to 25.0% of Cr by mass is subjected to cold plastic working, and the components are joined and fastened, and then the outer surface is welded or brazed. A metal foil having a composition of any one of (1) to (5) and having a thickness of 10 μm or more is attached to a part of the contact gap structure part with the part and the component. A method of manufacturing a fuel tank or fuel pipe with excellent corrosion resistance.
(13) The fuel tank or the fuel pipe having excellent corrosion resistance according to the above (12), wherein an organic layer or an inorganic layer for suppressing elution of the metal is provided on the surface of the metal foil after the metal foil is attached. Method.
(14) A steel plate or a steel pipe containing 9.0 to 25.0% of Cr by mass is subjected to cold plastic working as a raw material, and the components are joined and fastened, and then the outer surface is welded or brazed. A metal layer having a composition of any one of (1) to (5) and having a thickness of 10 μm or more is sprayed on a part of the contact gap structure part between the part and the component. A method of manufacturing a fuel tank or fuel pipe with excellent corrosion resistance.
(15) The fuel excellent in corrosion resistance according to (12), wherein after spraying the metal layer, an organic layer or an inorganic layer that suppresses elution of the metal on the surface of the sprayed metal layer or inside the sprayed metal layer is provided. Manufacturing method of tank or fuel pipe.
(16) A steel plate or a steel pipe containing 9.0 to 25.0% of Cr by mass is subjected to cold plastic working as a material, and after joining and fastening the components, the outer surface is welded or brazed. Part or part of the contact gap structure part with the component parts, a powder or granular metal having an average particle diameter of 1 to 100 μm and having a composition according to any one of the above (1) to (5). A method for producing a fuel tank or a fuel pipe having excellent corrosion resistance, characterized by coating a film having a metal content of 75% or more by mass% with a thickness of 10 μm or more on the outer surface.
(17) A steel plate or a steel pipe containing 9.0 to 25.0% of Cr by mass is subjected to cold plastic working as a material to join and fasten the components, and then weld or braze the outer surface. Part or part of the contact gap structure part with the component parts, a powder or granular metal having an average particle diameter of 1 to 100 μm and having a composition according to any one of the above (1) to (5). A fuel tank or a fuel pipe having excellent corrosion resistance, characterized in that a coating film having a thickness of 10 μm or more and a metal content of 75% or more by mass% is formed by applying a coating material composed of a resin and an isocyanate resin. Production method.
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, as a material for a fuel tank or a fuel pipe in the present invention, a steel plate or a steel pipe containing 9 to 25% of Cr is used.
Cr is a main element that controls the corrosion resistance of the material, and if it is less than 9%, the effect of increasing the pH of the metal in contact with the metal cannot be sufficiently obtained, and the external corrosion resistance becomes insufficient. On the other hand, Cr is a solid solution strengthening element, and if it is contained in excess of 25%, the ductility of the material is deteriorated and sufficient cold workability cannot be obtained. For this reason, the Cr content of the material is limited to 9 to 25%.
Alloy elements other than Cr, for example, Ni, Mo, Cu, etc., may be appropriately contained according to a known technique. However, even when these elements are contained, it is a necessary condition that the Cr content satisfies the above range.
The above-mentioned Cr-containing steel sheet or steel pipe is usually formed by cold working such as pressing, bending, expanding, drawing, seam welding, spot welding, projection welding, brazing, or mounting of metal fittings. The fuel tank and the fuel pipe are molded through the molding and assembling steps of the above, and after the molding is completed, the fuel tank and the fuel pipe are subjected to anticorrosion work on the outer surface exposed to the salt damage environment. In particular, since local corrosion susceptibility such as pitting corrosion, crevice corrosion, and SCC is high in a welded part, a brazed part, and a contact gap structure part with a metal fitting, it is necessary to construct at least a part of these parts.
In the case of the gap structure, if the size of the gap opening is sufficiently large, it is more preferable to construct the gap not only outside the gap but also inside the gap. In addition to this, it is desirable to apply the method to a non-welded portion having a high tensile residual stress. In addition, the welded part and the brazing part referred to here are the part where the passive film is destroyed and discolored by the heat of welding or brazing, the gap structure part formed by welding or brazing, and the brazing material part of brazing. Collectively.
Next, the indirectly contacting metal will be described.
The external corrosion protection in the present invention utilizes two effects of a cathodic protection effect and a material surface pH increasing effect. Therefore, the metal to be connected must be at least sufficiently base with respect to the stainless steel material. In the present invention, as a guideline, a necessary condition is that an electrode potential measured in a 5% NaCl aqueous solution at 30 ° C. is −0.4 V or less based on a saturated calomel electrode.
The measurement of the potential is performed over a period of 24 hours, and the highest value during the measurement is defined as a representative value. This potential corresponds to the re-passivation potential of the corrosion gap of stainless steel, and the potential of the stainless steel material drops below the re-passivation potential of the corrosion gap by placing a metal having a potential lower than this. By doing so, the growth of crevice corrosion can be suppressed.
Representative metal elements satisfying this condition include Zn, Al, and Mg. Among them, Zn is excellent in the effect of increasing the pH of the stainless steel material surface in addition to the cathodic protection effect. Since the basic zinc carbonate generated by self-corrosion raises the pH to the alkaline range, corrosion of the material is suppressed if Zn rusting is developed even in a part beyond the reach of the anticorrosion current when Zn is contacted. Because For this reason, Zn is the most effective metal as a means for achieving the object in the present invention.
Al is a metal lower than stainless steel in an external salt damage environment, and a cathode corrosion protection effect can be secured. Al is a metal that is useful for securing the cathodic protection effect for a long time because the self-corrosion rate is smaller than Zn. However, since the effect of increasing the pH is inferior to that of Zn, it is desirable to use an alloy with Zn, Mg, or the like when anticorrosion is to be performed on a portion exceeding the reach of the anticorrosion current.
Mg is a metal lower than Zn, and is suitable for cathodic protection under thin liquid film conditions having high resistance. However, since the self-corrosion rate of Mg is higher than that of Zn, the corrosion protection current can reach a wide range, but is consumed in a short time. Also, the effect of increasing the pH is inferior to that of Zn. For this reason, in order to secure a long-term cathodic protection effect and a pH increasing effect, Mg is desirably used as an alloy with Zn, Al, or the like.
As the metal system which reduces the self-corrosion rate while maximizing the two effects of the cathodic protection effect and the pH increasing effect, Zn contains 10% or more, and the balance is Al or Al, Mg, Si, or Al, Mg, An alloy composed of Sn or Al, Mg, Si, Sn is effective. The Zn content in these alloys needs to be 10% as the minimum from the viewpoint of ensuring a sufficient cathodic protection effect and a pH increasing effect due to rusting of Zn.
Mg forms a water-soluble intermetallic compound with Si or Sn in an Al-Mg-Si-Zn-based, or Al-Mg-Sn-Zn-based, or Al-Mg-Si-Sn-Zn-based alloy, It has a pH increasing effect and forms an anticorrosion film on the substrate to suppress corrosion. For this reason, when Mg is used as an alloy element, it is used together with Si, Sn, Al, and Zn, and the content is limited to a content sufficient to form an intermetallic compound. I do.
Si and Sn form water-soluble intermetallic compounds Mg 2 Si and Mg 2 Sn together with Mg, and effectively act on corrosion prevention. Therefore, when Mg is used, it is contained together. The content is in a range necessary for forming an intermetallic compound with Mg, and 1 to 10% is appropriate.
The form of contact of the metal or alloy having the above composition is not particularly limited as long as electrical conduction with the outer surface of the main body of the fuel tank or fuel pipe is ensured. Conventional methods include adhesion or adhesion through thermal spraying, coating as metal powder-containing paint, welding, brazing, or mechanical fixing using clips or bolts and nuts. Examples of the method include a method of sticking to a site of concern, a method of laminating a film as a powder or a particle on a site of concern for corrosion, and a method of coating and forming a film having a high metal content.
When a foil-like metal is used for corrosion protection at a corrosion-prone site such as a weld or a gap, the thickness of the foil is required to be 10 μm or more, preferably 50 μm or more, from the viewpoint of long-term corrosion protection. Furthermore, in order to suppress the corrosion and consumption of the foil, it is desirable to provide an organic layer or an inorganic layer for shielding the foil surface from the environment. A commonly used resin-based coating is sufficient for the organic layer, and a chromate film or the like is effective for the inorganic layer.
When a powder or a granular material is formed as a laminated film structure, the specific surface area of the metal adjacent to the material becomes larger than in the case of a foil, so that the anticorrosion effect is increased. The thermal spraying method is suitable for easily forming a powder or a granular material. In this case, the film thickness must be at least 10 μm or more, preferably 50 μm or more.
On the other hand, since the consumption is faster due to the larger specific surface area, it is desirable to provide an organic layer or an inorganic layer for shielding the film surface and particles in the film from the environment from the viewpoint of extending the corrosion life of the film. As the organic material layer, generally used resin-based paint is sufficient, and as the inorganic material layer, a chromate film or the like is effective. The thermal spraying means does not need to be particularly defined, and a normal flame spraying method or the like is sufficient.
The method of coating and forming a film on a site of concern for corrosion as a metal powder-containing coating is the most excellent form as a simple method capable of securing conductivity and suppressing corrosion and abrasion of a metal in contact. In this case, the content of the metal powder for securing the conductivity needs to be 75% or more by mass% with respect to the coating film. The size of the contained metal powder is appropriately from 1 to 100 μm as an average particle size. If it is too large, the coating workability is reduced. If it is too small, the metal powder is quickly consumed and the anticorrosion effect is reduced. A desirable metal powder size is 2 to 20 μm. The thickness of the coating film must be at least 10 μm or more, and preferably 50 μm or more.
The resin component of the paint is preferably an epoxy type or a urethane type from the viewpoint of ensuring the adhesion of the coating film, but a urethane type having particularly excellent water adhesion is optimal.
When using an epoxy resin, it is necessary to roughen the base by blasting or paper polishing in order to ensure sufficient adhesion.However, in the case of a urethane resin, the adhesion is excellent, Coarsening is not required, and it is suitable for the production of fuel tanks and fuel pipes from the viewpoint of productivity.
The urethane resin is formed by polymerization of isocyanate and a compound having a hydroxyl group such as polyol or water. However, from the viewpoint of coating workability, the urethane resin is a one-pack type of an isocyanate resin which is polymerized and cured by moisture in the air. It is desirable to use one. In this case, an appropriate amount of a curing accelerator such as an amine may be added as needed for the purpose of shortening the curing time.
It is not necessary to particularly define the coating means, and ordinary spray coating or the like is conventional.
Examples Hereinafter, the present invention will be described in more detail based on examples.
(Example 1)
A seam welded test piece having the dimensions and shape shown in FIG. 1 was prepared by simulating a flange portion of a fuel tank from a steel plate having a composition shown in Table 1 and having a thickness of 0.8 mm. In the drawing,
Alloy foils 2 (thickness: 0.2 mm) of various compositions were bonded to the welded portion 4 with a
As the corrosion test, assuming a salt damage environment on the outer surface of the tank, a combined cycle test in the JASO mode (5% NaCl solution spraying, 35 ° C, 2 hours → forced drying, 60 ° C, 4 hours → wet 90% RH, 50 ° C, 2 hours) for 300 cycles.
After the test was completed, the degree of local corrosion in the weld and the inside of the gap and the corrosion thickness of the alloy sheet were evaluated. If the ratio of the local corrosion depth and the alloy wear thickness to the base plate thickness is 20% or less, it is evaluated as good. If it exceeds 60%, it is evaluated as impractical. If it is 20 to 60%, there is a risk. Was evaluated.
Table 2 shows the test conditions and results. No. In the present invention of Nos. 1 to 12, a satisfactory anticorrosion effect is obtained at the welded portion and the gap. No. No. 8 has a large amount of alloy consumption. By suppressing the consumption of Zn by surface coating as in 1, the anticorrosion effect can be extended.
On the other hand, in Comparative Example No. Samples 101, 102, 103, and 104 are tested as welded, and the welds and gaps are severely corroded. When γ-based stainless steel is used as a material, SCC occurs.
(Example 2)
In the same manner as in Example 1, a seam welded test piece having the dimensions and shape shown in FIG. 2 was prepared from a steel plate having a composition shown in Table 1 and having a thickness of 0.8 mm by simulating the flange portion of the fuel tank. In FIG. 2,
The thermal spraying was performed by a flame spraying method in the atmosphere, and the thickness of the thermal sprayed layer was 8 to 200 μm. Some of the test pieces were subjected to chromate-silica-based chromate treatment after thermal spraying. The amount of adhesion was 20 mg per 1 m 2 of the surface of the sprayed layer in terms of Cr.
The coating is performed by spray coating a coating composed of alloy powders (average particle size: 3 μm) of various compositions and isocyanate, and then curing the coating in a room at room temperature to obtain a coating having a thickness of 8 to 100 μm and an alloy content in the coating of mass%. The film was formed at 68 to 85%. The corrosion test method and the evaluation method were the same as in Example 1.
Table 3 shows the test conditions and results of the thermal spray material. No. In the present invention of 21 to 32, a satisfactory anticorrosion effect is obtained at the welded portion and the gap. No. In No. 28, the amount of the sprayed layer was large. As in 21, the consumption of Zn can be suppressed by the chromate treatment after thermal spraying, and the anticorrosion effect can be extended.
On the other hand, in Comparative Example No. In No. 201, the sprayed thickness is out of the range of the present invention, and a sufficient anticorrosion effect is not obtained. In Comparative Example No. Sample 202 has insufficient corrosion prevention in the gaps because the material is out of the component range of the present invention.
Table 4 shows the test conditions and results of the coating materials. No. In the present invention of Nos. 41 to 52, a satisfactory anticorrosion effect is obtained at the welded portion and the gap.
On the other hand, in Comparative Example No. In Nos. 301 to 303, the metal content in the coating film is comparative example No. No. 304 indicates the coating film thickness, and Comparative Example No. 305 has insufficient corrosion protection at the welded portions or gaps because the components of the material are outside the range of the present invention.
(Example 3)
Using a steel pipe having the composition shown in Table 1 as a raw material, silver brazing test pieces having dimensions and shapes shown in FIGS. 3 and 4 simulating a joint portion with a breather tube in a fuel pipe were produced.
FIG. 3 shows the shape of a test piece when an alloy foil is placed on a silver brazing portion. In the figure, 7 is a fuel pipe body of a test material, 8 is a breather tube, the same material as 7, 9 is a seal at the end of the tube, 10 is a silver brazing part, 11 is an alloy foil, and (a) the center of the figure. The hatched area indicates the bonding area. (A) AA 'section of the figure is shown in the (b) figure. (B) In the drawing, 10 is a silver braze, 11 is an alloy foil, and 12 is a conductive adhesive layer for bonding the silver braze portion and the alloy foil.
FIG. 4 shows the shape of a test piece when the alloy is placed on the silver brazed portion by spraying or painting. In the figure, 7 is a fuel pipe main body of a test material, 8 is a breather tube, the same material as 7, 9 is a seal at the end of the tube, 10 is a silver brazing portion, and 11a is a sprayed or painted portion. (A) AA 'section of the figure is shown in the (b) figure. (B) In the drawing, 10 is a silver solder, and 11a is a sprayed layer or a coating film.
Alloy foils (thickness: 0.2 mm) of various compositions adhered to this silver brazed portion with a conductive adhesive, alloys of various compositions sprayed at a thickness of 0.1 mm, various compositions A coating composed of an alloy powder (average particle size: 3 μm) and isocyanate was spray-coated to prepare a coating having a coating thickness of 80 μm and an alloy content in the coating of 80%, and was subjected to a corrosion test. Further, under some test conditions, a material in which a urethane / epoxy resin-based coating film was formed on the surface of an alloy foil or an alloy sprayed layer was used. The corrosion test method and the evaluation method were the same as in Example 1.
Table 5 shows the test conditions and results. No. In the present invention of 61 to 72, a satisfactory anticorrosion effect is obtained at the welded portion and the gap.
On the other hand, in Comparative Example No. Nos. 401 to 405 are tested with silver brazing, and local corrosion of the brazing portion and SCC occur. Comparative Example No. In the case of 405, since the components of the material are out of the range of the present invention, a sufficient effect cannot be obtained even if anticorrosion work is performed.
[Brief description of the drawings]
FIG. 1A shows a corrosion test piece simulating a flange portion of a fuel tank, in which a conductive adhesive layer is provided and a metal foil is attached.
FIG. 1B is a sectional view taken along the line AA ′ of FIG.
FIG. 2A shows the shape and dimensions of a corrosion test piece simulating a flange portion of a fuel tank.
FIG. 2B is a sectional view taken along the line AA ′ of FIG.
FIG. 3A shows an example of a corrosion test piece simulating a brazing portion of a fuel pipe with a breather tube, and shows an example in which a metal foil is adhered.
FIG. 3B is a sectional view taken along the line AA ′ of FIG.
FIG. 4A shows an example in which a sprayed layer or a coating film is formed in a shape of a corrosion test piece simulating a brazing portion of a fuel pipe with a breather tube.
FIG. 4B is a sectional view taken along the line AA ′ of FIG.
Claims (17)
Applications Claiming Priority (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001167123 | 2001-06-01 | ||
| JP2001167123 | 2001-06-01 | ||
| JP2001313070 | 2001-10-10 | ||
| JP2001313070 | 2001-10-10 | ||
| PCT/JP2002/000895 WO2002099154A1 (en) | 2001-06-01 | 2002-02-04 | Fuel tank or fuel pipe exhibiting excellent corrosion resistance and method for manufacturing the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP3545759B2 JP3545759B2 (en) | 2004-07-21 |
| JPWO2002099154A1 true JPWO2002099154A1 (en) | 2004-09-16 |
Family
ID=26616225
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2003502261A Expired - Lifetime JP3545759B2 (en) | 2001-06-01 | 2002-02-04 | Fuel tank or fuel pipe excellent in corrosion resistance and method of manufacturing the same |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US6953062B2 (en) |
| EP (1) | EP1394282B1 (en) |
| JP (1) | JP3545759B2 (en) |
| DE (1) | DE60222659T2 (en) |
| WO (1) | WO2002099154A1 (en) |
Families Citing this family (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7341795B2 (en) * | 2002-07-01 | 2008-03-11 | Jfe Steel Corporation | Fe-Cr alloy structure with excellent corrosion resistance and excellent adhesion, and manufacturing method thereof |
| US20040222193A1 (en) * | 2003-05-06 | 2004-11-11 | Venkatasubramanian Ananthanarayanan | Method for resistance welding/brazing a tube to a member |
| US6875944B2 (en) * | 2003-05-06 | 2005-04-05 | Delphi Technologies, Inc. | Method for resistance welding/brazing a tube to a container |
| KR100997168B1 (en) * | 2003-06-19 | 2010-11-29 | 다이니폰 인사츠 가부시키가이샤 | In-mold label system plastic container |
| US7476824B2 (en) * | 2004-07-07 | 2009-01-13 | Delphi Technologies, Inc. | Welding apparatus for resistance welding heat exchanger tube to tubesheet |
| US7253372B2 (en) * | 2004-07-07 | 2007-08-07 | Delphi Technologies, Inc. | Method for welding heat exchanger tube to tubesheet |
| US20060016788A1 (en) * | 2004-07-23 | 2006-01-26 | Suhre Ryan J | Method for welding employing current |
| JP2006137360A (en) * | 2004-11-15 | 2006-06-01 | Nippon Steel & Sumikin Stainless Steel Corp | Fuel tank or fuel pipe excellent in salt damage/corrosion resistance |
| JP2006144040A (en) * | 2004-11-16 | 2006-06-08 | Nippon Steel & Sumikin Stainless Steel Corp | Method for producing highly corrosion resistant fuel based component having excellent productivity |
| CA2776892C (en) | 2006-05-09 | 2014-12-09 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic stainless steel excellent in resistance to crevice corrosion and formability |
| TWM328530U (en) * | 2007-07-13 | 2008-03-11 | Ways Tech Corp Ltd | Composite structure of faucet |
| JP5462583B2 (en) * | 2008-10-24 | 2014-04-02 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet for EGR cooler |
| US9802715B2 (en) * | 2012-03-29 | 2017-10-31 | The Boeing Company | Fastener systems that provide EME protection |
| KR101526658B1 (en) * | 2013-05-07 | 2015-06-05 | 현대자동차주식회사 | Wear-resistant alloys having a complex microstructure |
| JPWO2017222031A1 (en) * | 2016-06-24 | 2019-04-25 | ユニプレス株式会社 | Attachment structure to a vehicle body of a tubular member connected to a fuel tank and piping structure |
| US11764654B2 (en) * | 2017-03-09 | 2023-09-19 | Aisin Corporation | Rotary electric machine member manufacturing method |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3859061A (en) * | 1973-04-23 | 1975-01-07 | Chromalloy American Corp | Corrosion resistant coating system for ferrous metal articles having brazed joints |
| US3922396A (en) * | 1974-04-23 | 1975-11-25 | Chromalloy American Corp | Corrosion resistant coating system for ferrous metal articles having brazed joints |
| US4036602A (en) * | 1975-11-26 | 1977-07-19 | Chromalloy American Corporation | Diffusion coating of magnesium in metal substrates |
| JPS62124296A (en) * | 1985-11-25 | 1987-06-05 | Toyo Kohan Co Ltd | Surface treated steel sheet having excellent seam weldability and paint adhesiveness and its production |
| US4885215A (en) * | 1986-10-01 | 1989-12-05 | Kawasaki Steel Corp. | Zn-coated stainless steel welded pipe |
| US4942922A (en) * | 1988-10-18 | 1990-07-24 | Crucible Materials Corporation | Welded corrosion-resistant ferritic stainless steel tubing having high resistance to hydrogen embrittlement and a cathodically protected heat exchanger containing the same |
| US5597656A (en) * | 1993-04-05 | 1997-01-28 | The Louis Berkman Company | Coated metal strip |
| CA2123470C (en) * | 1993-05-19 | 2001-07-03 | Yoshihiro Yazawa | Ferritic stainless steel exhibiting excellent atmospheric corrosion resistance and crevice corrosion resistance |
| DE69500502T2 (en) * | 1994-02-08 | 1998-02-12 | Sumitomo Metal Ind | Process for producing a clad pipe |
| US5590691A (en) * | 1994-05-02 | 1997-01-07 | Itt Corporation | Extruded multiple plastic layer coating bonded to a metal tube |
| DE69738417T2 (en) * | 1996-07-01 | 2008-12-04 | Nippon Steel Corp. | RUST-PROOF STEEL PLATE FOR A FUEL TANK WITH EXCELLENT GAS-SEALITY AFTER WELDING AND CORROSION RESISTANCE BY FORMING |
| ES2181254T3 (en) * | 1997-08-12 | 2003-02-16 | Sandvik Ab | STEEL ALLOY FOR COMPOSITE TUBES. |
| JP2000203588A (en) * | 1998-10-19 | 2000-07-25 | Nisshin Steel Co Ltd | A1-plated steel sheet for fuel tank and production of fuel tank using the same |
| JP2000240855A (en) * | 1999-02-25 | 2000-09-08 | Sanoh Industrial Co Ltd | Covering pipe material |
| US6276400B1 (en) * | 1999-06-08 | 2001-08-21 | Itt Manufacturing Enterprises, Inc. | Corrosion resistant powder coated metal tube and process for making the same |
| JP2002211255A (en) | 2001-01-15 | 2002-07-31 | Toyota Motor Corp | Fuel tank for automobile |
| JP3952861B2 (en) * | 2001-06-19 | 2007-08-01 | 住友金属工業株式会社 | Metal material with metal dusting resistance |
-
2002
- 2002-02-04 WO PCT/JP2002/000895 patent/WO2002099154A1/en active IP Right Grant
- 2002-02-04 US US10/343,721 patent/US6953062B2/en not_active Expired - Lifetime
- 2002-02-04 JP JP2003502261A patent/JP3545759B2/en not_active Expired - Lifetime
- 2002-02-04 DE DE60222659T patent/DE60222659T2/en not_active Expired - Lifetime
- 2002-02-04 EP EP02710495A patent/EP1394282B1/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE60222659T2 (en) | 2008-06-19 |
| EP1394282A1 (en) | 2004-03-03 |
| JP3545759B2 (en) | 2004-07-21 |
| US6953062B2 (en) | 2005-10-11 |
| WO2002099154A1 (en) | 2002-12-12 |
| EP1394282B1 (en) | 2007-09-26 |
| DE60222659D1 (en) | 2007-11-08 |
| US20030196715A1 (en) | 2003-10-23 |
| EP1394282A4 (en) | 2006-05-31 |
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